I think one of the problems is is that I don't have enough
choices to make. I don't feel like I'm in control at all, if I move up or down away from enemies, they just follow me and my situation doesn't change at all. The best I can do is sometimes (maybe) go into a dead end to make it so that only one enemy can engage me at once. The recent update of being able to go into enemy squares gives another dimension of choice, but the game needs more.
Without the option of choice, the game feels unfair, like it's railroading you.
I also don't feel
addicted. (I'd read that article if you haven't already, I found it very interesting.)
Let's compare your game's addictiveness to Bejeweled:
1. The game is simple to understand; two clicks and you're in. This is mostly true. At first I was trying to use the arrow keys to move around, but afterwards I got the game mechanics pretty quick.
2. The game presents a clear problem with a clear solution (make rows of 3+ jewels). Yes, the clear solution is to defeat the enemies? and reach the goal.
3. The results of action frequently create cascading consequences. If you do something stupid, you lose health for that level. The only way this doesn't apply is because your health resets every level.
3a. These cascading consequences have an element of randomness / unpredictability / intermittent reward. This doesn't exist in your game at all.
Something I would do to try to make the game addictive is to add random health drops off of monsters, then make it so that your health remains continuous throughout the game.
(This is just off of my analysis though, not particularly out of opinion.)
Sound effects will definitely make it more immersive. I can totally imagine what it would sound like, I just think it could really use a quick implementation of it.